Learning the distinguishing features of different invertebrates

Submitted by jon@wildmosaic.eco on

Is there a summary anywhere of the distinguishing features of different invertebrates? So, if I get the chance, I'm able to try to photograph those aspects.

For example, butterflies are generally easy... hoverflies... I'm at a bit of a loss but probably stripes and head?

Slugs it's the breathing hole and underside, snails.. shell colour?

Bees... whatever you can get before they fly away.

Grasshoppers and crickets... ?!?

Appreciate I could buy the relevant guide for each particular group and learn that way. But that would be expensive and my bookcase is already overflowing, so hoping there might be a summary somewhere.